U.S. Pat. No. 7,163,361B2 discloses a cutting tool of the abovementioned field, which includes an insert holder and a narrow cutting insert secured in a pocket therein. The insert has an open design, in the sense that it includes an extension, or root portion that extends outwardly downwards from a bottom surface. In an assembled position of the cutting tool, the extension is wedged between a flexible jaw and a non-flexible jaw in the pocket. Due to the open design of the insert, the flexible jaw externally abuts the root portion. Furthermore, it is well known in the field that a longer wedge arrangement performs better than a shorter one.